Wikipedia has a lot of info about when the song was written; mlb.com suggests 1971, but it seems like it should have been earlier given the song’s immediate popularity. Any other ideas?
As the song seems to have been written in 1908, with a second version in 1927, I think c.1908 is a good guess for first usage.
Looks like a quick jump from its being written in 1908 to being a hit at the Follies.
The next year:
I don’t see any kind of evidence that statement is true.
I’ve searched extensively through newspaper accounts from 1908-1950, and the best info I can find is that in or around the 1938-40 period, a minor league team in Seattle, WA claimed that they were the only place in the US that sang the song during the seventh inning stretch.
I could find no evidence that singing the song was common at the ballparks in 1910, or even that it happened. But someone may be able to provide evidence that it did. I’ll look some more as time permits today.
Anecdotal evidence only, but my Dad and I sang it at the ballpark in the 50’s.